DIY ESS - Energy Provider statement shows inverted low & high rate usage for October and December between 2012 & 2013

I have been charging (Forced Charge Mode on my ESS) at night for several months now since there is less Solar Production in winter. 

My last energy bill shows that, compared to last year october to december period, I inverted the usage in low rate and high rate

From Oct to Dec 2012 :  (no Solar and no ESS)

  ->   700 kWh used at night rate (half price)

  -> 1002 kWh used during the day 

From Oct to Dec 2013 : (Solar and ESS with Forced Charge Mode at Night 10:30 PM to 6:30 AM))

  -> 1021 kWh used at night rate (half price)

  ->   734 kWh used during the day

The funny thing is that the amount paid is more or less the same because price per kWh is rising, always ...


For more info on my DIY ESS, check out this other dedicated blog : http://www.diyesskit.com